Manufacture of ferrophosphorus.



JOHN J. GRAY, JR., or

PATENT OFFICE,

ROGKDALE, TENNESSEE.

MANUFACTURE oF FERROPHOSPHORUS.

Specification of Letters E'atent.

Patented Sept. 18, 1906.

Application filed November 5, 1904. Serial No. 231,590.

1 y smelting in a blast-furnace a mixture containing iron ore, phosphate rock, or other natural phosphorusbearing compound, and a silicious material in suitable proportions. I

My improved process may be carried out under such conditlons as W1ll produce ferrophosphorus having any desired phosphorous content up to the limit of saturation.

Prior to my invention ferrophosphorus was not produced commercially in this country, and the demand for the same had been supplied from abroad, Where it is made man electrical furnace.

Attempts have been made to produce commercially ferrophosphorus in a blast-furnace or a cupola by smelting certain-kinds of ore and phosphorusbearing compounds; but in all such cases it has been thought necessary to use in conjunction with iron-bearing ore a manufactured product containing phosphorusras, for example, phosphoric slag. This slag was charged into a cupola with the ore and coke, the continual burning of which freed the phosphorus from said slag and permitted its continuous absorption by the iron until the desired roportion of hosphorus was obtained. Modi cations of t 1is charge, treated in a blast-furnace, have been proposed, in which phosphate of lime or apatite was added, the phosphoric slag being retained in all cases, however, as the essentialphosphorus-bearing material; but in all previous attempts to manufacture this material either the higher cost of production, due to the character of the materials and the manner of treating them, or

' the failureto secure a product of uniform and regular com osition has prevented the successful pro uction commercially of ferrophosphorus suitable for use in the manufacture of steel by the open-hearth process, in which ferrophosphorus is added after the steel is made and remains in the finished product.

I have discovered that I can use the natural iron ore of any desired degree of richness and natural materials for effecting the liberation of phosphorus from the phosphorusbearing compound in an. ordinary blast-furmace and its absorption by the iron and that I can control to any desired degree the percentage of phosphorus absorbed by and combined with the iron by regulating the amount of silicious material -used with the flux, Whether such silicious material be an independent charge or occurs in the ore to be treated. As a result of this discovery I am enabled to produce ferrophosphorus of aregular and uniform quality, in which the phosphorous content may be of any desired amount from one per cent. up to thirty or thirty-five per cent, or even the limit of saturation In carrying out my process any ordinary furnace with the usual equipment of hot-blast stoves, engines, and boilers may be used, and such a furnace is charged with ordinary iron ore, silicious material, and phosphate rock in a manner similar to that when making ord inary pig-iron, and the process of smelting is conducted in a manner similar to that used in the production of said pig-iron.

' In order to make a product of a specified phosphorus content, an analysis is made of the average iron ore, silicious material, and phosphate rock to be used, and simple calcu: lation on the basis of the proportion of iron and the phosphorous and silicious material is made to determine the weight of the respective materials necessary for each charge to'give the desired amount of phosphorus 1n the finished product. Due allowance must be made for the loss of iron and phosphorus in the furnace and in the cinder or slag, which amounts can be very closely approximated by a skilful furnace-man or may be found by experiments, such loss varying somewhat according to the character of materials used and the conditions of the furnace used in the manufacture of the product. It should be noted that care must be exercised in the operation of the furnace to obtain the desired phosphorous content and the heat and blast regulated from time to time to adapt them to the varying conditions of the furnace, as will be understood by those skilled in the art.

When the smelting operation is complete, the product may be cast, as pig-iron is cast, in sand beds, chilled molds, ladles, or castingmachines, as may be desired.

As it is possible to find an iron ore carrying the desired amount of silicious material, the iron and silicious material being combined in one natural compound, it would not be necessary in such case to charge an independent that T silicious material, but simply the iron ore and phosphate rook. Again, as-it is possible to find a phosphate rock hearing such silicious material which, if of sufficient uantity to effect the liberation of the speci ed percentage of phosphorus in the finishedproduct, would likewise dispense with the necessity for an independent silicious material in the charge, and the latter. need only contain iron ore and phosphate rock.

.I find in carrying out my improved process can obtain'a product with any desired amount of phosphorus-simply by using more or less of the phosphate of lime and that more or less of this material may be used successfully by increasing or decreasing the amount of silicious material, which latter is fiuxed by the lime in the phosphate of lime. This fact makes my process one of ready control through the simple operation of varying the amount of said silicious material used relaphosphorus by my rocess.

tively to the amount of phosphate of lime the'ferrophosphorus can be made to vary, as

desired, by intelligent management of the furnace.

phorus, which consists in charging a Any grade of ore in combination with a silicious material and phosphate rock can be so mixed as to make any grade'of ferrophos: phorus desired from one per cent; to thirty or thirty-five per cent.

I claim 1. The process of producing ferrolphosurnace .With a mixture of iron ore, a neutral phosphate, and 'sufiicient silica to free. the desired amount of phosphorus itherefrom, and then smelting the mixture.

'- 2. The process of producing ferro hos- 1plhoru's, which co'nsistsin charging a lastrnace with a mixture containing natural iron ore, phosphate rock, and a silicious material in predetermined pro ortions .to liberate the percentage of phosp orus required to combine with the iron, and then smelting said furnace charge. v

3. The process of making ferrophos horus, which consists in charging a blasturnace with a mixture containing natural iron ore,

lastphosphate rock, and asilicio'us material in v predetermined proportions to liberate the percentage of p osphorus'required to combine with the iron, smelting said furnace charge, and controlling the phosphorous'content by varying the. amount .of silicious material relativelyto the amount of phosphate rock;

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN J. GRAY, JR.

Witnesses: i

Jos. F. JOHNSTON,

E. D. JOHNSTON.- 

